Electronically steered antennas (ESA), also known as phased array antennas, combine multiple individual transmit/receive (T/R) modules which may be implemented as single phase shifter chips and antennas to create a larger effective aperture. The electronically controlled phase and gain relationship between the individual T/R modules controls the radiation pattern and therefore directivity of the synthesized aperture. This control over the radiation pattern can be used for beam steering in air and space-borne communication systems, for target acquisition and tracking or for the synthesis of deep nulls for clutter suppression in radar systems.